Synergistic effect of microscopic buckle and macroscopic coil for self-powered organ motion sensor

Although soft mechano-electrochemical energy harvesters have attracted considerable attention as wearable sensors, they face challenges, including low output performance, high Young's modulus and low energy-conversion efficiency. To address these limitations, we introduce a novel design featuring macroscopically coiled and microscopically buckled fibres to improve the mechano-electrochemical energy-harvesting capability, thereby maximising capacitance change and affording higher electrical output. The harvester achieved a gravimetric peak current density of 121 A/kg and a peak power density of 16 W/kg. Moreover, the harvester showed enhanced stretchability under a strain of over 400 %, low Young's modulus of 0.2 MPa and an energy conversion efficiency of 0.33 %. Furthermore, when implanted in a pig's bladder, it showed minimal impact during expansion and contraction thanks to its softness and provided real-time electrical output in response to static and dynamic volume changes.